an indurated marl.
Origin of marlstone
Also called marl·ite [mahr-lahyt] /ˈmɑr laɪt/.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a type of marl that contains clay and calcium carbonate and is resistant to the decomposing action of air
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012